Apparatus and method for embedding components in small-form-factor, system-on-packages

ABSTRACT

According to various aspects of the present disclosure, an apparatus is disclosed that includes a small form factor mobile platform including a system-on-package architecture, the system-on-package architecture arranged as a stack of layers including a first layer having a first conformable material; a second layer having a second conformable material; one or more electronic components embedded within the stack of layers; and a heat dissipating element configured dissipating heat generating from the one or more electronic components, wherein the first conformable material, the second conformable material, or both are configured to allow high frequency signal routing.

BACKGROUND

1. Field of the Invention

The present invention relates generally to integrated circuit design,and more particularly, to a small-form-factor (SFF), system-on-package(SOP) architecture having one or more of improved performance,integrated thermal management and interference mitigation within theSFF-SOP environment.

2. Description of the Related Art

Mobile platforms are getting smaller in size and incorporating moreelectronic and wireless functionalities for efficient communications. Inorder to include all the desired electronic functionalities into thefuture small-form-factor (SFF) mobile platforms, embeddedsystem-on-package (SOP) architectures are being developed.

Currently different active component as well as passive componentembedding techniques are being developed using multilayer substratematerials and cavities. Device embedding techniques are being developedusing low-cost materials which are not good for embeddingradio-frequency (RF) functionalities. Some approaches to embed‘integrated-passive-devices’ are being developed which may increase thecost of manufacturing and assembly, which tends to minimize the purposeof using low-cost material system. Moreover, RF-performance andsize-reduction remains difficult to achieve for multi-standard wirelesssystems. RF-IPDs (Integrated Passive Devices) are also being utilized onsilicon, low temperature co-fired ceramic (LTCC), glass or othermaterials and embedded into the low-cost material systems for RFconnections. This potentially increases the cost of assembly andmanufacturing considerably and degrade/changes the performance ofcomplex passive structures after other component embedding or shieldingin close proximity.

On the other hand, high-performance materials are being utilized whichare perceived to have higher cost than digital-substrate materials.These materials can embed complex RF passive designs in multilayermaterial environment. Thermal and noise management issues are not yetsolved in the current SOP structures. The conventional electromagneticband-gap (EBG) structures for noise-mitigation in the SFF-SOPenvironment will tend to consume significant space and will increase theoverall SOP size. Both of these approaches also suffer from cross-talkthermal issues.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a cross-section of a SOP with both high-performance andlow-performance polymer layers to form a stack of materials inaccordance with various embodiments of the present invention.

FIG. 2 shows another cross-section of a SOP with both high-performanceand low-performance polymer layers to form a stack of materials inaccordance with various aspects of the present disclosure.

FIG. 3 a shows a cross-section of a SOP, which includes embeddedisolation structures in accordance with various aspects of the presentdisclosure.

FIG. 3 b shows vertical periodic micro-via structures A and B, takenalong the lines A and B of FIG. 3 a.

FIG. 3 c shows horizontal periodic structures, taken along the line C ofFIG. 3 a.

DETAILED DESCRIPTION Definitions

High-performance material: High-performance material is a material thatprovides superior electrical properties including low loss and lowcoefficient of thermal expansion (CTE) characteristics versus theproperties of a low-performance material.

In accordance with various aspects of the present disclosure, anapparatus is disclosed that includes a small form factor mobile platformincluding a system-on-package architecture, the system-on-packagearchitecture arranged as a stack of layers including a first layerhaving a first conformable material; a second layer having a secondconformable material or any other rigid organic material; and one ormore electronic components embedded within the stack of layers; a heatdissipating element configured dissipating heat generating from one ormore electronic components, wherein the first conformable material, thesecond conformable material, or both are configured to allow highfrequency signal routing.

In accordance with various aspects of the present disclosure, the heatdissipating element can be arranged between the first and the secondlayers. The heat dissipating element can include a high-conductivitymaterial, such as metal, or a directional conductor. Thehigh-conductivity metal can be selected from the group consisting ofcopper, aluminum, KOVAR, which is a heatsink material, bronze,silicon-carbide or other materials such as gold or silver and thedirectional conductor can include graphite that is configured todissipate heat along a two-dimensional plane. Moreover, the apparatuscan include features wherein the first conformable material and thesecond conformable material are the same material or are differentmaterials. Further, the apparatus can include features wherein the firstconformable material, the second conformable material, or both include apolymer, such as a liquid crystal polymer or can be a rigid organic orpolymer material. Further, the apparatus can further include a thirdlayer having a third material.

In accordance with various aspects of the present disclosure, theapparatus can further include a vertical filtering structure arrangedbetween the one or more electronic components. The vertical filteringstructure can include stacked via patterns, arranged in a periodicarrangement of the vertical filtering structure that can define afiltering characteristic. The apparatus can include features wherein thevertical filtering structure is configured to filter or isolateradio-frequency noise, harmonics of digital noise, or both produced bythe one or more electronic components. Moreover, the apparatus caninclude features wherein the third material is different than the firstand the second conformable materials.

In accordance with various aspects of the present disclosure, a methodis disclosed that includes forming a small form factor mobile platformincluding a system-on-package architecture, the system-on-packagearchitecture arranged as a stack of layers including providing a firstlayer of a first conformable material; providing a second layer of asecond conformable material; embedding one or more electronic componentswithin the stack of layers; arranging a heat dissipating element in thestack of layers to dissipate heat generated from the one or moreelectronic components, wherein the first conformable material, thesecond conformable material, or both are configured to allow highfrequency signal routing.

In accordance with various aspects of the present disclosure, the heatdissipating element can be arranged between the first and the secondlayers. The first conformable material and the second conformablematerial can be the same material or different materials. For example,the first or second conformable material, or both can include a polymer,such as a liquid crystal polymer or can be a rigid organic or polymermaterial. The heat dissipating element can include a high-conductivitymaterial, such as metal, or a directional conductor, wherein thehigh-conductivity metal can be selected from the group consisting ofcopper and aluminum and the directional conductor can include graphitethat is configured to dissipate heat along a two-dimensional plane.Further, the apparatus can further include a third layer having a thirdmaterial.

In accordance with various aspects of the present disclosure, the methodcan include arranging a vertical filtering structure between the one ormore electronic components, wherein the vertical periodic filteringstructure includes stacked via patterns. The arrangement of the verticalfiltering structure can be periodic and define a filteringcharacteristic, wherein the vertical filtering structure is configuredto filter or isolate radio-frequency noise, harmonics of digital noise,or both produced by the one or more electronic components. The verticalfiltering can be combined with the horizontal periodic filtering asallowed by the small-form-factor SOP in consideration.

These and other objects, features, and characteristics of the presentinvention, as well as the methods of operation and functions of therelated elements of structure and the combination of parts and economiesof manufacture, will become more apparent upon consideration of thefollowing description and the appended claims with reference to theaccompanying drawings, all of which form a part of this specification,wherein like reference numerals designate corresponding parts in thevarious FIGS. It is to be expressly understood, however, that thedrawings are for the purpose of illustration and description only andare not intended as a definition of the limits of the invention. As usedin the specification and in the claims, the singular form of “a”, “an”,and “the” include plural referents unless the context clearly dictatesotherwise.

FIG. 1 shows a cross-section of a SOP with both high-performance andlow-performance polymer layers to form a stack of materials inaccordance with various aspects of the present disclosure. Theheterogeneous stackup, shown generally at 100, includes one or morelayers of high-performance material 105, and one or more layers oflow-performance material 110. By way of a non-limiting example, thehigh-performance material 105 may be a polymer, such as a liquid crystalpolymer (LCP), Rogers RXP or any other material that exhibits superiorelectrical properties compared to those of low-performance material 110over a wide frequency range. Low loss tangent is a factor for thehigh-performance material 105 and is directly related to circuit signallosses and quality or Q factor. Because of these characteristics, thehigh performance materials, such as LCP, allow for high frequency signalrouting and passives. The low-performance material 110 may include apolymer, such as ABF (Ajinomoto Build-up Film), FR4, BT or any otherorganic materials.

The high-performance materials 105, like LCP, may be more flexible orpliable than the low-performance material 110. This flexibility of thehigh-performance material 105 allows these layers to conform aroundelectrical components, such that the electrical components may beembedded between layers of the high-performance material. In someaspects, a particular layer of the stackup may include both the high-105and low-performance material 110. In this case, the electrical and/orthe RF component may be arranged within layers of a high-performancematerial and adjacent to low-performance materials on a particular layerof the SOP.

By way of a non-limiting example, the stackup as shown in FIG. 1 can beless than 0.5 mm thick. The vertical dimension of the SOP may be reducedby thinning the substrates. In this case, the embedded IC designs, ifnecessary, may be optimized to include the effect of thin substrates aswell as polymer material environments.

In some aspects, the stackup can be a homogeneous stackup include onlyone type of layers. For example, stackup can include layers of thehigh-performance material or layers of low-performance material.

The stackup may include different active ICs components 115, includingdifferent electrical and/or radio-frequency components, that may bearranged between layers of high-performance material 105. By way of anon-limiting example, the different electrical ICs may include a poweramplifier (PA) 120 such as GaAs PA. Moreover, the different radiofrequency ICs may include a combination chipset of two highly integratedICs such as RFIC and BB/MAC IC 125, which may operate under the IEEE802.11n and IEEE 802.11a/b/g standards. Other chipset operating underdifferent wireless standards may also be used. These ICs are not limitedto those used in wireless application, but can include ICs such asmemory, general purpose processors, or application specific ICs andSOCs. The stackup may also contain one or more passive components 130that may be either a radio-frequency (RF) component that consume (butdoes not produce) energy, or a component that is incapable of a powergain. Examples of RF passive components may include capacitors,inductors, resistors, transformers, high-rejection multiband RF filters,multiplexers and baluns. Other passive components, such as an antenna135, can be embedded within layers of the multilayer metals to achievehigher RF-performance. RF-signals from the silicon-integrated singlechip such as RFIC 125 may be routed using the layers of high-performancematerials 105 whereas digital signals may be routed using the layers oflow-performance materials 110 through metal lines 140.

In various aspects of the present disclosure, a rolled version ofhigh-performance liquid crystal polymer (LCP) materials may be used forembedding RF-actives and develop embedded RF-passives using theLCP-multi-metal-substrate layer structures. The rolled versions of LCPare typically less expensive than the original LCP materials. Thisallows the SOP form-factor (all x-, y-, z-directions) to be minimized bydesigning the optimized high-performance passive components in theLCP-type layers around the embedded active components. The LCP-typematerials will allow the substrate materials to conform around theembedded active components and reduce the need for any surfaceprotection around the embedded active components. Thin layers of LCP(≦25 μm thick) type materials may be used as re-distribution layers forefficient RF-, analog- and digital-signal distribution to achievesmall-form-factor. Lower-cost ABF-type materials may be used in thestackup to embed additional digital functionalities.

In accordance with various aspects of the present disclosure, the SOP asshown at 100 may be modified by including one or more heat dissipatingelements. The one or more heat dissipating elements may be arrangedwithin a homogenous stack of materials, such as a stack of materialshaving only high-performance material or only low-performance material.The one or more heat dissipating elements may also be arranged within aheterogeneous stack of materials, such as a stack having both high- andlow-performance material. As shown in FIG. 1, the one or more heatdissipating elements, such as heatsink materials 150, can be arrangednear the high-power active components to dissipate the heat generated bythe active component. In a non-limiting example, the heat dissipatingelements are in a layer above, or directly on top of, the activecomponent. The heat dissipating element may be arranged between layersof the high-performance material or between layers of the high- andlow-performance material. The heat dissipating elements may be ahigh-conductivity material, such as metal, and can include copper,aluminum, KOVAR (KOVAR is a trademark of Carpenter TechnologyCorporation and is a nickel-cobalt ferrous alloy designed to becompatible with the thermal expansion characteristics of borosilicateglass in order to allow direct mechanical connections over a range oftemperature) and silicon carbide (SiC), or a directional conductor suchas graphite, which dissipates heat in a two-dimensional (x-, y-) plane.Combination of different heat dissipaters and stacked via patterns,discussed further below, can be utilized for realizing optimal heatsinking structures. By this arrangement of the one or more heatdissipating elements within the small-form-factor SOP, the need for anexternal heat sink may be reduced or eliminated.

In accordance with various aspects of the present disclosure, thinsheets of thermal materials may be embedded in the LCP type materialsdue to the conformable properties of high-performance LCP. The thinsheets of copper, graphite, KOVAR, silicon-carbide, brass and othermaterials with good thermal properties may be embedded under ICs withhigh-power dissipation (such as PA) to enable thermal management withinthe SOP architectures and still maintain SFF properties. The LCPs can beset around the materials to conform and create SOPs without any voids orgaps. Graphite materials disperse heat in the X-Y direction and may beembedded in certain cases to spread the heat to thermaldissipators/metal-vias, discussed further below, to take the heat outfrom the embedded SOP structure.

FIG. 2 shows another cross-section of a SOP with both high-performanceand low-performance polymer layers to form a stack of materials inaccordance with various aspects of the present disclosure. FIG. 2 issimilar to FIG. 1, but shows power amplifier 120, GaAs PA, mounted ontop of the substrate. For small IC components such as GaAs PA, they neednot be embedded since they do not occupy a large area on the substrate.A molding layer 205 may be arranged over the top-mounted component toencapsulate and protect the SOP.

FIG. 3 a shows a cross-section of a SOP, which includes embeddedisolation structures in accordance with various aspects of the presentdisclosure. The embedded isolation structures are configured andarranged to reduce noise coupling and crosstalk issues in a very smallform factor SOP. Similar to the heat dissipating structure describedabove, the isolation structure may be arranged within a homogenous stackof materials, such as a stack of materials having only high-performancematerial or only low-performance material. Also, the isolationstructures may also be arranged within a heterogeneous stack ofmaterials, such as a stack having both high- and low-performancematerial. ICs are shown in FIG. 3 a, IC1 (305), IC2 (310) and IC3 (315),arranged among the high-performance materials of the SOP. Also, one ormore passive components 320 are shown embedded within layers of thehigh-performance material. Isolation structures 325 may be embeddedwithin the SOP to reduce noise coupling and crosstalk issues in the SOP.

FIG. 3 b shows vertical periodic micro-via structures A and B, takenalong the lines A and B of FIG. 3 a. The vertical micro-via structures330 are configured and arranged to reduce element-to-elementnoise-coupling/crosstalk. The characteristic of the crosstalk isolationcan be tuned by changing the periodicity of the vertical structures.FIG. 3 c shows horizontal periodic isolation structures 335, taken alongthe line C of FIG. 3 a. Both the vertical and horizontal structures maybe combined to create improved isolation in the complete SOPenvironment. These isolation structures may be used to surround theradio or digital functional blocks in order to isolate the RF noise aswell as harmonics of digital noise.

In some aspects of the present disclosure, faraday cages and horizontalelectronic bandgap (EBG) structures using patterned metals may be usedfor the isolation structures. Moreover, the vertical periodic structuresmay also be combined with the horizontal EBG metal patterns to formeffective noise reducers around desired parts of the SOP.

Although the invention has been described in detail for the purpose ofillustration based on what is currently considered to be the mostpractical and preferred embodiments, it is to be understood that suchdetail is solely for that purpose and that the invention is not limitedto the disclosed embodiments, but, on the contrary, is intended to covermodifications and equivalent arrangements that are within the spirit andscope of the appended claims. For example, it is to be understood thatthe present invention contemplates that, to the extent possible, one ormore features of any embodiment can be combined with one or morefeatures of any other embodiment.

1. An apparatus comprising: a small form factor mobile platformincluding a system-on-package architecture, the system-on-packagearchitecture arranged as a stack of layers including: a first layerhaving a first conformable material; a second layer having a secondconformable material; one or more electronic components embedded withinthe stack of layers; and a heat dissipating element configureddissipating heat generating from the one or more electronic components,wherein the first conformable material, the second conformable material,or both are configured to allow high frequency signal routing.
 2. Theapparatus according to claim 1, wherein the heat dissipating element isarranged between the first and the second layers.
 3. The apparatusaccording to claim 1, wherein the first conformable material and thesecond conformable material are the same material.
 4. The apparatusaccording to claim 1, wherein the first conformable material and thesecond conformable material are different materials.
 5. The apparatusaccording to claim 1, wherein the first conformable material, the secondconformable material, or both include a polymer.
 6. The apparatusaccording to claim 1, wherein the heat dissipating element includes ahigh-conductivity material or a directional conductor.
 7. The apparatusaccording to claim 6, wherein the high-conductivity material is selectedfrom the group consisting of: copper, aluminum, brass, silicon-carbide(SiC) or KOVAR.
 8. The apparatus according to claim 6, wherein thedirectional conductor includes graphite that is configured to dissipateheat along a two-dimensional plane.
 9. The apparatus according to claim1, further comprising: a vertical filtering structure arrangedperiodically between the one or more electronic components.
 10. Theapparatus according to claim 9, wherein the vertical periodic filteringstructure includes stacked via patterns.
 11. The apparatus according toclaim 9, wherein the periodic arrangement of the vertical filteringstructure defines a filtering characteristic.
 12. The apparatusaccording to claim 9, wherein the vertical filtering structure isconfigured to filter or isolate radio-frequency noise, harmonics ofdigital noise, or both produced by the one or more electroniccomponents.
 13. The apparatus according to claim 1, further comprising:a third layer having a third material that is different than the firstand the second conformable materials.
 14. A method comprising: forming asmall form factor mobile platform including a system-on-packagearchitecture, the system-on-package architecture arranged as a stack oflayers including: providing a first layer of a first conformablematerial; providing a second layer of a second conformable material;embedding one or more electronic components within the stack of layers;and arranging a heat dissipating element in the stack of layer todissipate heat generated from the one or more electronic components;wherein the first conformable material, the second conformable material,or both are configured to allow high frequency signal routing.
 15. Themethod according to claim 14, wherein the heat dissipating element isarranged between the first and the second conformable materials.
 16. Themethod according to claim 14, wherein the first conformable material andthe second conformable material are the same material.
 17. The methodaccording to claim 14, wherein the first conformable material and thesecond conformable material are different materials.
 18. The methodaccording to claim 14, wherein the first conformable material, thesecond conformable material, or both include a polymer.
 19. The methodaccording to claim 14, wherein the heat dissipating element includes ahigh-conductivity material or a directional conductor.
 20. The methodaccording to claim 19, wherein the high-conductivity material isselected from the group consisting of: copper, aluminum, brass,silicon-carbide (SiC) or KOVAR.
 21. The method according to claim 19,wherein the directional conductor includes graphite that is configuredto dissipate heat along a two-dimensional plane.
 22. The methodaccording to claim 14, further comprising: arranging a verticalfiltering structure periodically between the one or more electroniccomponents.
 23. The method according to claim 22, wherein the verticalperiodic filtering structure include stacked via patterns.
 24. Themethod according to claim 22, wherein the periodic arrangement of thevertical filtering structure defines a filtering characteristic.
 25. Themethod according to claim 22, wherein the vertical filtering structureis configured to filter or isolate radio-frequency noise, harmonics ofdigital noise, or both produced by the one or more electroniccomponents.
 26. The method according to claim 14, further comprising:arranging a third layer having a third material that is different thanthe first and the second conformable materials.